A number of machines have been developed to eliminate the hand detasseling of seed corn which is necessary in hybrid seed corn production in which six rows of corn are detasseled and the next two rows are left with the tassels on to pollenate the six detasseled rows. Seed corn production requires 100% detasseling of the six rows, and a satisfactory machine must remove more than 95% of the tassels, and preferably in excess of 98%. The remaining tassels are hand stripped.
Detasseling is carried out long before the corn plants are mature, and a problem with most detasseling machines is that they either remove or destroy too many of the upper leaves which are needed for maximum plant growth. Furthermore, most prior art machines tend to leave too many tassels because they lack adequate means for guiding the upper end portions of twisted or misaligned corn plants into the detasseling heads.
The most pertinent prior art patents known to applicant are Dostal U.S. Pat. No. 2,397,249 and Cler U.S. Pat. No. 3,769,782. The former has a detasseling head with a pair of longitudinally extending rollers the surfaces of which are held firmly in contact by a compression spring at the rear of one roller; and the rollers have rubber surfaces with spiral grooves that tend to feed the tassels and leaves rearwardly; and the rollers snap the tassels upwardly out of their sockets. The powerful gripping action of the rollers tends to remove the upper leaves with the tassels. The apparatus of the Cler patent has a pair of rollers with intermeshing studs which also tend to remove the leaves with the tassels and in some cases can even pull an entire corn plant out of loose soil.